1. Field of the Invention
The present invention relates to a displaceable working platform having an extensible boom, and more particularly, to a mine working platform which is displaceable along a mine shaft and secured immovably at a desired position in the mine shaft with the extensible boom extending at a desired angle thereto so as to be extended into a working area which is progressively bored in a secondary shaft usually at an angle to the mine shaft.
2. Description of Prior Art
Various apparatuses are known for use in mine shafts to effectuate the boring of shafts or to drill holes in the walls of mine shafts. Such apparatus is, for example, described in Canadian Patent 989,814 issued on May 25, 1976. Such devices can be operated locally or remotely and are used to bore into mineral veins in a direction forwardly of the vehicle. The above-described Patent relates to a self-propelled drilling rig for boring blast holes and small diameter wells and as the well is excavated, the rig moves in the direction of excavation. A disadvantage of such rigs is that the rigs must be pulled out and repositioned in the well each time it effectuates a task. Also, the main frame is usually positioned very close to the drilling rig and this can be hazardous to a person working in close proximity to the rig, particularly in mine shafts where the support where the floor of the shaft is at an angle and often slanted sideways and strewen with debris. Also, the apparatus as defined in this Patent shows the jig manipulator mounted on a carriage which provides for only a small travel extension of the drilling tool and accordingly it is necessary to displace the main frame each time a small distance has been bored. This is very time-consuming and costly and also hazardous to the mine workers.
It is therefore desirable to provide a machine which supports a mine worker or a mine working tool over long distances in mine shafts or along excavated veins disposed transversely to mine galleys and wherein the working implement can be easily and qwuickly retracted from the excavating tunnel without having to displace the main support frame each time the tool is retracted and repositioned.
Telescopic booms which are secured to turret type bases and articulated thereon are also known in the crane design art, such as disclosed in Canadian Patent 2,000,107. However, like the prior art referred to above, a disadvantage of such design is that the boom is pivotally fixed to the main frame and restricted thereby. The boom is connected to work primarily in the forward direction of the frame for the reason that the counterweight is provided in the rear end of the frame and the anchoring can only be effectuated in the rear end so as to be out of the way of the boom displacement area. For this reason, such cranes have imposed limitations on the angular displacement of the boom, particularly in the lateral plane at an angle to the long axis of its support frame. The apparatus of the above-referred to Canadian Patent is accordingly utilized to work primarily in the forward direction of its support frame or vehicle frame and accordingly must be displaced in the tunnel where a work function is to be performed.